Wood heel making machine



Jan. 4, 1938 Q H, BERTRAM 2,104,115.

' WOOD HEEL MAKING MACHINE Filed May 14, 1931 7 Sheets-Sheet -1 Fig". l.

H. A. BERTRAM WOOD HEEL MAKING MACHINE v Jan. 4, 1938.

Filed May 14, 193] i 7 Sheets-Sheet 2 FigtZ.

Jan. 4, 1938. 1-1. A. BERTRAM WOOD HEEL MAKING MACHINE Filed May 14, 1951 71 Sheets-Sheet a Jan. 4, 1938.

H, A. BERTRAM WOOD HEEL MAKING MACHINE Filed May 14, 195] 7 Sheets-Sheet 4 A/l/E/V/WP Jan. 4, 1938. H. A. BERTRAM 2, ,1

WOOD HEEL MAKING MACHINE Filed May 1;); 193] 7 Sheets-Sheet 5 462 i- 132 3' QEWM 15g 128 140 IMAM!!! m i i I m: '154 7/ /i 172 i -kw Y A 14354! Jan. 4, 1938. H. A. BERTRAM WOOD HEEL MAKING MACHINE Filed May 14, 1931 7 Sheets-Sheet 6 Fig. 8

Jan. 4, 1938. H. A, BERTRAM 2,104,115

WOOD HEEL MAKING MACHINE Filed May 14, 19:51 7., Sheets-Sheet '7 FlgTS.

AVE/WM? Patented Jan. 4, 1938 UNITED STATES PATENT OFFICE WOOD HEEL MAKING MACHINE Hugo A. Bertram,

Malden, Mass., assignor to United Shoe Machinery Corporation, Paterson, N. .L, a corporation of New Jersey Application May 14, 1931, Serial No. 537,371

caving machine.

By the concaving operation is meant the out- .i ting out of the concave attaching face of a heel.

blank. This is customarily done after the breast, back and side surfaces have been formed. It was for many years the custom to concave wood heel blanks on a machine having a babbitt form for gripping the heel blank and carrying it under a cutter. Such a machine is shown in United States Letters Patent No. 796,194, granted August 1, 1905, on application of Fred A. Day. This machine was expensive in use, owing to the necessity of providing a special holding form for every type of heel blank.

A still further improved machine is shown in United States Letters Patent No. 17,942, reissued January 27, 1931, on the application of Carl I.

22') Pollard. This machine has the fiat slotted table and cutter, as above described, and the heel blank is reciprocated forward and back over the cutter by an automatic mechanism comprising a jacking means which engages'the blank at separated .33 points around its tapering periphery, and holds it down against the flat table. This has the advantage that the same jacking means will work successfully on almost any style of heel blank, as no fitting of the periphery as a whole is required, and

H this improvement constituted a substantial advantage over the Day machine.

It is a principal object of this invention to improve still further the Pollard machine while preserving its advantages of automatic operation and.

universal jacking. I have provided a gage at the end of the cutter slot in the flat table and mechanism for rotating the heelblank over the cutter with its edge against the gage. I am thus enabled to produce a rim of uniform width around the cupped attaching'face of the blank, a characteristic which is required by present day standards in wood heel making.

A principal feature of the invention results in increased production. Inasmuch as a rotation of I about 180 is required to concave a heel blank, I have provided two opposed jacking mechanisms, so that a rotation of 180 will cause one of them to come empty to the loading position when the other arrives at the finishing position with a finished heel blank, thus avoiding all loss of time in getting a jack to the loading and starting position. These jacks, in accordance with. another feature of the invention, are so arranged that only one of them can be in closed, or in an operative, blank holding, condition at once (though both can be open at once), thus avoidingdanger of damage by dragging a finished blank .beyond the finishing position. I

Preferably, and in accordance with the inven- I tion, the illustrated heel blank moving mechanism comprises two properly timed and related cams,

one of which translates the blank over the cutter and the other of which rotates it. In this connection I have provided a mounting for the jack mechanism consisting of a gate-like member swinging freely over the table so that the heel blank can be kept in proper contact with the gage at all times, irrespective of any exact accuracy in relationship between the shape of the heel blank and the shapes of the cams. The same cams therefore are adequate to handle any style of heel. blank.

These and other features of the invention comprising certain combinations and arrangements of parts will be apparent from the following description of a preferred embodiment of the invention shown in the drawings, in which Figs. 1 and 2 are the upper and lower parts of a complete side elevation;

Fig. 3 is a plan;

Fig. 4 is a plan section on the line IV-IV of Fig. 1;

Fig. 5 is a side elevation of the jacks;

Fig. 6 is a section on the line VIVI of Fig. 5; Fig. '7 is a sectional plan on the line VIIVII of Fig. 5, showing the starting position;

Fig. 8 is a similar sectional plan on. the line VIIIV'III of Fig. 1, showing the mechanism at the half-way point of the operative cycle;

Fig. 9 is a section on the line IX-IX of Fig. 7;

Fig. 10 is a view like Fig. 9 but showing a Cuban heel blank and holding member specially adapted for it; I

Fig. 11 showsa sectional'elevation through the. heel blank at a time during the first quarter of the operational cycle; and

Fig. 12 shows the finished heel blank and illustrates the operative cycle of the machine.

The main frame It] has a fiat top or table I2, and a shelf l4, on which the driving motor 16 is mounted. The motor shaft drives a cutter shaft i8 directly through a belt 29, and drives a countershaft 22 by a belt 24. The countershaft 22 is belted to a second countershaft 26, connected by a sprocket chain 28 to a sprocket Wheel on a shaft 39, mounted in the frame I0, and miter-geared to a vertical shaft 32 through a clutch 34.

The clutch 34 consists of a member 36integral with the miter-gear 31 and having several pins 38 projecting from its upper surface. The member 40 is mounted fixedly on the shaft 32 and has a vertically slidable spring-pressed pin 42 with a shoulder 44 on its side. The clutch lever 46 is pivoted at 48 and has a beveled end as indicated in dotted lines in Fig. 2, behind the shaft 32. This beveled end normally'projects into a groove 50 in the member 40. The lower part of the shaft 32 in Fig. 2 has been shown rotated about 180 relatively to the upper part, in order to show the pin 42, this part of the .mechanism being about half through its cycle. path of movement of the pins 38 and is driven thereby to turn the shaft 32. in the cycle of rotation the beveled shoulder 44 of the pin 42 will slide up over the beveled end of the lever 46 and lift the pin 42 above the ends of the pins 38, and the drive will stop.. The clutch is set again by the treadle 52 and cord 54 which rotate the lever 46 to release the 'pin 42,and.let

it fall into the path of the pins 38.

The upper end of the shaft 32 is, mounted in a V bracket 55 on the frame I0, and carries mecha- -to swing in a. horizontal plane.

from above.

nism for operating the jack mechanism 56. 'As already stated, this jack mechanism is so moved as to pull a heel blank 58 over the cutter 59,

which projects through a slot GI in the table I2, and turn the heel blank about 180 while so doing.

The jack mechanism 56 is hung on a gate-like member or arm 60, pivoted on the shaft 32 so as Its end 62 works in a supporting guideway 64 and a weight 66 is fastened to it by a cord 68 passing over a pulley 'I0, to pull it clockwise, against a stop 65, as seen '12 in which is mounted a vertical shaft I4, having a rectangular slide block I6 fixed at its lower end. This block I6 is located between two slidable cheek-plates I8 bolted to a plate 80 having a cam slot 82 in it. The cheek-plates support the jack mechanism which will be described below. The shaft I4 extends through a slot 84 in the plate 80, to permit the sliding movement on the block I6 above-mentioned.

The plate 80 is moved back and forth over the block I6, to effect the translational movement of the heel blank, by a roller 86 mounted on a bar 88 which can move rectilinearly on a slide 90 on the bearing I2, and on a sliding pin-and-slot connection at 92 with the shaft 32. The bar 88 is operated by a roller 94 running in a cam slot 96 in a plate 98 pinned to the shaft 32. Fig. 4 shows the starting position. The first 90 of movement of the shaft 32 pulls the bar 88 to the extreme right, the next pushes it back to the extreme left, and the last 90 pulls it back to the right, to

the initial position. The jack mechanism par takes of these movements only to a certain degree, owing to the fact that it must also slide on the rotating block III, as will be seen.

pivoted pawl I08 on it. This is held in place by a cap I09 shown as broken away in Fig. 3. The

pawl I88 is arranged to engage the teeth I02 as occasion arises. A rack bar IIII running in a guideway in the gate 60 engages the gear teeth I06 to turn the arm I04. This rack bar has a rigid extension 2 having a pin-and-slot connection at II3 with the shaft 32, and having a roller II 4 running in a cam slot'I I 6 in a plate H8 fastened to the shaft 32. The first 90 of rotation of the shaft 32 throws the bar I I0 to the The pin 42 lies in the About 180 later The gate is provided with a bearing V apart, and vice versa.

The block I0 is rotated by the shaft 14, which extreme left in Fig. 3, the pawl I08 moving counterclockwise over the disk I00 and falling into a tooth'l02 just'prior to the end of this movement. The next 180 of rotation of the shaft 32 pulls the bar IIII clear to theright, rotating the shaft I4 and:block I5 exactly 180, and the final 90 returns the bar H0 toward the left, while the pawl I08 runs back idly over the edge of the disk I 00. A spring-pressed latch I20 is mounted to slide in the bar 88 to engage either of two notches I22 in the edge of the plate 80. This latch is pulled out of operative position by a lever I24 which strikes an abutment I26 on the gate 60 just before the 90 point of rotation of the shaft 32. This unlocksthe' plate 80 and permits the -The jacking mechanism will now be, described (Figs. 5 and 6). V V

The cheek-plates I8 are connected by a cross plate I28 having a central rib I30 (Fig. 6) and two slideways I32, in which work rightand leftthreaded blocks I34. These blocks are V-shaped (Fig. '7) with the points of the Vs extending toward the center of the jack'and have little horizontal guideways' I36 'on their V edges; These four guideways are connected in pairs by two V blocks I38, extending across from one to the other of the blocks I34 and running in the little guideways I36. Thus movement of the blocks I34 toward each other by means of the right and left screw I40 will cause theblocks I38 to move The screw I40 is freely rotatable in the rib I38, and is held against sidewise movement therein. by 2. lug I4I engaging a reduced portion atits' center. Each block I38 has guides in which slide two gage .blocks I42, which are right and left-threaded and are operable by right and left screws I44, which adjust the distance between the gage blocks but keep them always cent red. As clearly shown in Fig. 9, the gage blocks are substantially spaced from the table I2, allowing the lip of a Louis heel blank to' extend under them.

' The heel blank 58 abuts the'gage blocks I42 the lugs I46 can be set to keep it properly centered, and to exert a downward pressure on its tapering lateral surfaces.

The heel is also, held in the jack by a springpressed plunger I48, pivoted on. a rod I40 slid-' ing in a tube I50 which is an integral part of a block I52 having two parallel projecting pins I54 sliding in guide holes in arms I56 of the cheekplates I8. These guide holes are at an angle of about 45 to the table. I2 and slope inwardly toward the vertical axis of the jack mechanism. When the. block I52 is forced downward the plunger I48 contacts with the back of the heel blank and holds it firmly down against the table I2 and against the gage blocks I42.

The blocks I52 are pin-and-slot pivoted to links I58 (Fig. 5) one at each end of each block,

the other ends of which are pivoted at I58 to the cheek-plates "I8. The upp r faces of these links lie against cams I60 pivoted on the cheek-plates and having crank-arms I62. The ends of the crank-arms on each side of the jack are connected by a cross-bar I64, by which they may be swung, and which unites them in a single compound crank-arm. These two compound crankarms are pin-and-slot connected by a link I66, the slots in which are so spaced that the two crank-arms cannot both be down at once, though both can be up at once. The blocks I52 are pulled up by springs I68 and the cams I66 are arranged to turn their high points a little past their contact points with the bars I58 as they force them down, so that the bars I58 and blocks I52 remain in lowered operative position when forced there. I

A gage I16 is adjustably mounted on the table I2 adjacent to the end of the slot 6| through which the cutter projects, and an adjustable guide I12 with a pointed nose I14 (Fig. 7) is provided on the other side of the cutter, to remove finished work.

Fig. 10 shows a modified form of heel blank holding mechanism 48. In this form the rod I49 has a pivoted member I16 with an adjustable abutment I18 and a fixed abutment I80. The abutment I18 is formed with a notch to rest on the bottom rear corner of the heel blank, and the abutment I86 is designed to rest on the back of the blank near the attaching face. This form of holder is useful in case of heels, such as Cubans, having a very steep slope at the back.

The mechanism for holding the heel blank is peculiarly effective, being'especially so upon a Louis heel blank. The gage block I42, lugs I46 and plunger I48 (Fig. 9) engage the blank at separated points of its tapering periphery, and tend to force it toward the table I2, holding it firmly and positively in position on the table, and the described adjustments of the block I42 and lugs I46 enable them to handle any style of blank whatever, without any necessity of making special holding devices which fit the special periphery of the instant blank. The raising of the lever I 62 frees the blank completely and instantly. In the case of Cuban blanks, which have no lip to extend under the gage block I42, the member I14 (Fig. 10) prevents any possible upward and backward movement of the heel blank.

In operating the machine, the operator stands with the machine in front of him as shown in Fig. 1; The left-hand lever I62 being up, he places a heel blank 56 in the gaging apparatus and throws the lever I62 down. This movement forces up the other lever I 62 on the right, releasing the finished blank on that side. He then steps on the treadle 52 and the machine starts. During the first quarter cycle the blank is pulled to the operators right. The edge'of its attaching face is drawn between the adjustable gage I 16 on the table and the cutter, and as the blank passes nearly rectilinearly over the cutter, this gage maintains a substantially uniform thickness of lip. In general the gate member 66 will swing slightly in its guideWay 64, the weight 66 holding the blankagainst the gage, at all times, but yielding to prevent any wedging and locking against the gage due to any tapering shape of the attaching face of the heel blank. This part of the operation forms a concave cut running from I82 to I84 (Fig. 12). The latch 526 is pulled back just before the end of this quarter cycle, and is released just after the beginning of the next. The next half cycle rotates the blank 180 clockwise as seen from above, the latch I20 sliding around the periphery of the plate until it falls into its other notch I22. This rotation is also combined with a certain translational movement relatively to the gate member. The rotation is about the center of the shaft 14, and the translation is a sliding movement on the'block 16, governed by the roll er 86 through its engagement with the slot 82, in the disk 80. The position of the roller 86 is governed by the cam slot 66, but the only vital requirement about the shape of this slot during the half cycle now being discussed is that it shall permit the roller 86 to be brought to the position shown in Fig. 4 when the block 16 has been rotated from the position there shown, and be such as to keep the mechanism from jamming. This part of the slot 96 (the right-hand half as seen in Fig. 4) is relieved on both sides, that is, it is wider than the diameter of the roll 94. Its inside edge is, closer to the center of the cam than the inside edge of the left-hand half of the slot, and its outside edge is farther from the center of the cam than the outside edge of the left-hand half of the slot. At the end of the first quarter cycle the plate 80 is located to the right of its Fig. 4 position, and as the shaft 14 v Meanwhile the previously finished and released blank has been pushed to the right during the first quarter cycle, and then pushed toward the operator by the rotation of the parts I36, I46 during the succeeding half cycle. this movement it strikes the pointed end I14 of the adjustable guide I12 (Fig. '1) on the table I2, which separates it from the jack mechanism and the operator brushes it into a barrel.

In Fig. '1 the position I88 shows the previously finished blank a little after the beginning of the operation, while the blank 58 is in starting position. This showing is to avoid covering the parts I42. Fig. 8 shows the blank 58 half way through the cycle and half way through the turn.

The last quarter cycle again moves the roller 86 to the right, pulling the blank being cut with it, cutting from I86 to I90 in Fig. 12, the gate and gage cooperating as before. The finishing position is at about I96 (Fig. 8). The machine stops automatically, as described above.

A discussion of the movement of the center about which the heel blank is turned may be instructive. This center is a point in the axis of the shaft 14. At the beginning of the operation this point in the axis of the shaft 14 is sub stantially at the point I82 (Fig. 12). During the first quarter cycle (when no turning takes place) it moves to the vicinity of the point marked I64 in Fig. 12. During the second quarter cycle, it moves back to the point I62, while the heel blank turns 90. During the third quarter cycle it moves back to I94, while the heel blank turns its second 90. During the fourth quarter cycle, it moves back to I 62 again, no turning taking place. The gate 66 swings back and forth accordingly, since the periphery of the heel blank is always against the gage I16.

The heel blank actually turns about the center of the shaft 14, but the center of the shaft 14 itself moves back and forth toward and from During,

the gage H0, in a fiat, horizontal, circular arc, the center of which is in the axis of the shaft 32. The length of this are and the position of the center of the shaft 14 on it, at any instant of the cycle, depend on the shape of the heel blank being treated, these considerations being governed by the continuous contact of the heel blank with the gage I10. 7

It will be observed that the cutter cuts away from the edge of the heel blank, thus avoiding chipping of the edge.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A wood heel concaving machine having two opposite heel blank holding mechanisms, a cutter, and means for rotating the heel blank hold- 7 ing mechanisms substantially 180 during each operative cycle of the machine about an axis,

perpendicular to the attaching face of a heel blank in one of said holding mechanisms, whereby the said heel blank holding mechanisms come alternately to the starting position of the operative cycle. I

2. A Wood heel concaving machine having two opposite heel blank holding mechanisms, a cut ter, and means for rotating the heel blank holding mechanisms substantially 180 about an axis located between the heel blank holding mechanisms and perpendicular to the attaching face of a heel blank in one of said holding mechanisms during each operative cycle of the machine, whereby the said heel blank holding flat table, a cutter pro ecting beyond the plane mechanisms come alternately to the starting position of the operative cycle.

3. A wood heel concaving machine having two oppositely arranged blank holding mechanisms, a cutter, and means for imparting during an operative cycle a movement of translation combined with a rotation of substantially 180 to the blank holding mechanisms, relatively to the cutter, whereby to make a U-shaped cut in a heel blank in the holding mechanism, and to bring the said blank holding mechanisms alternately to the starting and finishing positions, respectively, of the operative cycle.

4. A wood heel concaving machine having two oppositely arranged blank holding mechanisms, a cutter, and means for imparting during an operative cycle a movement of translation combined with a rotation of substantially 180 about a movable axis, to the blank holding mechanisms, relatively to the cutter, whereby to make a U-shaped cut in a heel blank in the holding mechanism, and to bring the said blank holding mechanisms alternately to the starting and finishing positions, respectively, of the operative cycle.

5. A wood heel concaving machine having a flat table, a cutter projecting through the table, a gage adjacent to the cutter, a heel blank holding mechanism, and means for moving the blank holding mechanism relatively to the cutter to make a U-shaped'cut in a heel blank in the hold ing mechanism, said movement comprising rotation of 180 only during an operative cycle of the machine.

6. A wood heel concaving machine having a flat table, a cutter projecting through the table, a gage adjacent to the cutter, two oppositely arranged heel blank holding mechanisms, and means for moving the blank holding mechanisms relatively to the cutter to make a U-shaped cut in a heel blank in a holding mechanism, said ranged heel blank holding mechanisms,andmeans for moving thelblank holding mechanisms relatively to the cutter to make a U-shaped cut in a heel blank in one of the holding mechanisms,

and for carrying the other holding mechanism from the finishing position to the starting position of the operative cycle, said movement comprising rotation of 180 only during an operative cycle of the machine.

7 8. A wood heel concaving machine having a flat table, a cutter projecting beyond the plane of the table, a heel blank jacking mechanism arranged to move in a plane parallel to the table and to carry a heel blank 'over the cutter in contact with the table,'and separate means for oscillating and rotating the jacking mechanism to form a U-shaped cut in the heel blank.

9. A wood heel concaving machine having a fiat table, a cutter projecting beyond the plane of the table, a heel blank jacking mechanism arranged to move in a'plane parallel to the table and to carry a'heel blank over the cutter in contact with the table, a cam for oscillating the jacking mechanism over the cutter, and a second cam for rotating the jacking mechanism over' the cutter, to form a U-shaped cut in a heel blank held in the jacking mechanism.

10. A wood heel concaving machine having a of the table, a heel blank jacking mechanism arranged to move in a plane parallel to the table and to carry a heel blank over the cutter in contact with the table, a cam for oscillating the jacking mechanism over the cutter, a second cam for rotating the jacking mechanism over the cutter, to form a U-shaped cut in a heel blank held in the jacking mechanism, and means for holding the heel blank in contact with the gage as it passes over the cutter.

11. In a wood heel concaving machine, a fiat table, a cutter projecting beyond the plane of the table, a jacking mechanism arranged to hold a heel blank in contact with the table, means for moving the jacking mechanism over the cutter to form a U-shaped cut in a blank held therein, said movement comprising a rotation of substantially 180", means for positively holding the jacking mechanism against rotation, and means for rende'ring said holding means inoperative at the time in the operative cycle that the rotation is to begin.

12. In a wood heel concaving machine, a flat table, a cutter projecting beyond the plane of the table, a jacking mechanism arranged to hold a heel blank in contact with the table, means for moving the jacking mechanism over the cutter 'to form a U-shap'ed cut in a blank held therein,

, stantially parallel to the plane of rotation of the cutter, a jacking mechanism movably mounted on the member, a sliding member for oscillating the jacking mechanism relatively to the member, a second sliding member for rotating the jacking mechanism relatively to the member, 7

whereby a heel blank in the jacking mechanism may be translated-and rotated over the cutter to form a U-shaped cut in the blank.

14. In a wood heel ooncaving machine, a rotating cutter, a member having free movement substantially parallel to the plane of rotation of the cutter, a jacking mechanism movably mounted on the member, a sliding member for oscillating the jacking mechanism relatively to the member, a second sliding member for rotating the jacking mechanism relatively to the member, whereby a heel blank in the jacking mechanism may be translated and rotated over the cutter to form a U-shaped cut in the blank, a gage, and means for moving the freely moving member to hold the edge of the blank against the gage during the formation of the. U-shaped cut.

15. In a wood heel concaving machine, a work supporting table, a cutter projecting beyond the plane of the table, heel blank holders having two oppositely arranged jacks, each jack having a contact member arranged to press upon the tapering periphery of a heel blank in the jack to press the blank toward the table, and means to impart a movement to the holder, comprising a rotation of only, to carry the heel blank over the cutter and to concave the attaching face of the blank.

16. In a heel concaving machine, a work support having its operative surface lying in a plane, a tool having its operative portion located on one side of said plane, a heel holder located on the same side of said plane and comprising elements arranged to engage the tapering periphery of a heel and to exert pressure on the. heel toward the said plane, and means for moving the holder and a heel held thereby, with the attaching face of the heel in said plane, over the tool, said movement comprising a rotation of 180 only.

1'7. In a heel concaving machine, a work support having its operative surface lying in a plane, a tool having its operative portion located on one side of said plane, a heel holder located on the same side of said plane and comprising a member arranged to be moved toward and from the said plane and, when moved toward the plane, to engage the tapering periphery of a heel with its attaching face in the plane and to press the heel toward the plane, andmechanism for effecting independent movements of translation and rotation to the holder parallel to the plane to carry the heel blank over the tool.

18. In a heel concaving machine, a work support having its operative surface lying in a plane, a tool having its operative portion located on one side of said plane, a heel holder located on the same side of said plane and comprising a pivoted member arranged to be swung toward the said plane to engage the tapering periphery of a heel with its attaching face in the plane and to press it toward the plane, and mechanism for effecting independent movements of translation and rotation to the holder parallel to the plane to carry the heel blank over the tool.

19. In a heel concaving machine, a work support having its operative surface lying in a plane, a tool having its operative portion located on one side of said plane, a heel holder located on the same side of said plane and comprising two jacking mechanisms, each having members arranged to engage a heel with its attaching face lying in said plane, at points on the periphery of a crosssection of the heel which is approximately parallel to the attaching face of the heel and to exert pressure on the heel substantially perpendicular to the plane, and mechanism for moving the holder parallel to the plane to carry the heel over the tool, said movement comprising a half rotation.

20. In a heel concaving machine, a work support having its operative surface lying in a plane, a tool having its operative portion located on one side of said plane, a heel holder located on the same side of said plane and comprising two jacking mechanisms, each having members arranged to engage a heel, the attaching face of which lies in the said plane, at separated points on the periphery of a transverse cross-section thereof which is substantially smaller than the attaching face of the heel, and to exert pressure on the heel in a direction toward its attaching face and transverse to the said plane, and mechanism for moving the holder parallel to the plane to carry the heel over the tool, said movement comprising a half rotation.

21. A wood heel con-caving machine having a blank holding mechanism, a cutter, and means for rotating the blank holding mechanism substantially 180 during each operative cycle of the machine, whereby the said blank holding mechanism moves alternately from the starting position to the finishing position of the operative cycle and vice versa.

HUGO A. BERTRAM. 

